<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>

<body>
    <div id="app">

    </div>
</body>

</html>
<script>
    const { createApp } = Vue;
    const vm = createApp({
        data() {
            return {
                message1: 'Hello'

            }
        }
    }).mount('#app1') 
</script>